Igbt light load efficiency

ABSTRACT

An apparatus comprising an insulated gate bipolar transistor and a super junction metal-oxide semiconductor field effect transistor wherein the insulated gate bipolar transistor and the super-junction metal-oxide semiconductor field effect transistor are electrically and optionally structurally coupled.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.16/585,388 filed Sep. 27, 2019, the entire contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

Aspects of the present disclosure generally relate to transistors andmore particularly to insulated gate bipolar transistors.

BACKGROUND OF THE INVENTION

A variety of modern applications use electronic switches to performdifferent functions during operation. While there are many differenttypes of electronic switches including relays, transistors and vacuumtubes. Currently solid-state transistors are predominantly used inelectronic circuits today. Two major types of transistors are InsulatedGate Bipolar Transistors (IGBTs) and metal-oxide semiconductor fieldeffect transistors (MOSFETs).

IGBTs have excellent high current conductance attributes compared toMOSFETs. The ‘on’ state conductance of a MOSFET is linear at a standardtemperature and can be modeled as a resistor using RDSon. On the otherhand, the conductance of an IGBT at a standard temperature is non-linearand is better modeled as diode. Additionally IGBTs are superior inhandling higher current densities compared to MOSFETs and also have asignificantly simpler/lower cost fabrication process compared to aSuper-Junction MOSFET. Thus, IGBTs are ideal for high currentapplication because of their relatively reduced resistance and relativereduced cost.

While there are many positive characteristics of IGBTs compared toMOSFETS, there are also some significant drawbacks. One drawback is thatIGBTs at low current have an ‘on’ state voltage threshold V_(th) and donot begin conducting until the voltage is above the threshold. Thismeans that for low amperage and voltage applications traditional IGBTshave significantly higher conduction losses compared to MOSFETs, whichbegin conducting in the ‘on’ state at a non-zero voltage without anydiode knee in their output characteristics. Another drawback of the IGBTis that due to its construction, it does not conduct current in thereverse current direction whereas MOSFETs have a built-in body diodethat allows reverse current direction conduction.

To overcome this problem a diode may be placed anti-parallel to the IGBTcommonly referred to as a freewheeling diode. Freewheeling diodesresolve the problem of reverse current direction conduction but donothing to solve the voltage threshold issue. Thus, it wouldadvantageous to configure an IGBT package that could conduct at lowamperages and have good reverse current conduction characteristics.

It is within this context that aspects of the present disclosure arise.

BRIEF DESCRIPTION OF THE DRAWINGS

Objects and advantages of aspects of the present disclosure will becomeapparent upon reading the following detailed description and uponreference to the accompanying drawings in which:

FIG. 1 is a schematic diagram of a prior art IGBT without a freewheelingdiode.

FIG. 2 is a circuit diagram depicting an example of prior art placementof a freewheeling diode in an IGBT.

FIG. 3 is a circuit diagram depicting an IGBT coupled to aSuper-junction MOSFET according to aspects of the present disclosure.

FIG. 4 is a side schematic diagram of an IGBT structurally coupled to asuper-junction MOSFET on the same substrate according to aspects of thepresent disclosure.

FIG. 5 is a bottom view schematic diagram of an IGBT structurallycoupled to a super-junction MOSFET on the same substrate according toaspects of the present disclosure.

FIG. 6 is a side view of an IGBT structurally coupled to asuper-junction MOSFET on the same substrate and having deepsuper-junction like trenches according to aspects of the presentdisclosure.

FIG. 7 is a side view of an IGBT having emitter and collectorconductively coupled to the source and drain of a super-junction MOSFET,respectively, according to aspects of the present disclosure.

FIG. 8A is a current vs voltage line graph showing the function of theIGBT structurally coupled to a super-junction MOSFET device at 25 Caccording to aspects of the present disclosure.

FIG. 8B is a current vs voltage line graph showing the function of theIGBT structurally coupled to a super-junction MOSFET device at 125 Caccording to aspects of the present disclosure.

FIG. 9A is a current vs voltage line graph showing the function in thereverse current reverse bias direction of the IGBT structurally coupledto a super-junction MOSFET device at 25 C according to aspects of thepresent disclosure.

FIG. 9B is a current vs voltage line graph showing the function in thereverse current reverse bias direction of the IGBT structurally coupledto a super-junction MOSFET device at 125 C according to aspects of thepresent disclosure.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Although the following detailed description contains many specificdetails for the purposes of illustration, anyone of ordinary skill inthe art will appreciate that many variations and alterations to thefollowing details are within the scope of the invention. Accordingly,the exemplary embodiments of the invention described below are set forthwithout any loss of generality to, and without imposing limitationsupon, the claimed invention.

Additionally, concentrations, amounts, and other numerical data may bepresented herein in a range format. It is to be understood that suchrange format is used merely for convenience and brevity and should beinterpreted flexibly to include not only the numerical values explicitlyrecited as the limits of the range, but also to include all theindividual numerical values or sub-ranges encompassed within that rangeas if each numerical value and sub-range is explicitly recited. Forexample, a thickness range of about 1 nm to about 200 nm should beinterpreted to include not only the explicitly recited limits of about 1nm and about 200 nm, but also to include individual sizes such as butnot limited to 2 nm, 3 nm, 4 nm, and sub-ranges such as 10 nm to 50 nm,20 nm to 100 nm, etc. that are within the recited limits.

In the following discussion of the illustrated examples, the firstconductivity type is typically N and the second conductivity type is P.However, it should be noted that substantially similar devices may befabricated using a similar process but with conductivity types oppositethose shown and described. Specifically, aspects of the presentdisclosure include implementations like those shown and described hereinin which N is substituted for P and vice versa.

IGBTs generally have better high amperage conductance characteristicsthan MOSFETs. IGBT's generally are constructed similar to MOSFETS exceptthey have an extra doped layer. Thus where a MOSFET may have a dopingorganization of N-doped layer, P-doped layer, N-doped layer. An IGBTwill have a doping organization of P, N, P, N or N, P, N. P.

FIG. 1 shows a prior art layer configuration of an IGBT. As shown theIGBT has a lightly doped drift region of a first conductivity type (e.g.N-doped) 107. The doping concentration of the drift region may bebetween 1e13 cm⁻³ and 5e14 cm⁻³ depending on the desired breakdownvoltage. Lower doping concentrations of the drift region result inhigher breakdown voltages. A more heavily doped buffer region of thefirst conductivity type 112 underneath the drift region 107. The dopingconcentration of the buffer can range from 1e15 cm⁻³ to 5e16 cm⁻³. Alightly doped layer 113 of either conductivity type, coming from thestarting substrate material exists under the buffer. The doping level oflayer 113 is typically below 1e15 cm-3. A heavier doped layer 114 of thesecond conductivity type is underneath the lightly doped region. Theheavier doped layer 114 forms the IGBT collector and can be implantedfrom backside or from frontside during epitaxial growth. Its dopinglevels range from 1e17 cm-3 to 1e19 cm-3. A collector contact metalliclayer is formed on the bottom of the collector 115.

On top of the lightly doped drift region 107 is a heavily doped regionof the first conductivity type 106. A body region 105 is located on topof the heavily doped region. The body region may be doped with thesecond conductivity type. The body region may be may have a dopingconcentration in the range of 1e17 cm⁻³ to 1e18 cm⁻³. The body region105 may have a heavily doped emitter region of the first conductivitytype formed on top of it 104. The doping concentration of the sourceregion may be above around 2e19 cm⁻³.

A shield trench may be formed in the substrate and terminate at thedepth of the lightly doped drift region 107. The shield trench may belined with a dielectric (e.g. an oxide layer) 111. A shield trenchelectrode 110 is disposed on top of the dielectric and may be at emittervoltage. The shield trench electrode may be for example apolycrystalline silicon layer. A planar gate comprising a planarinsulating layer (e.g. an oxide layer) 108 and a gate insulating layer109 is formed on top of the shield electrode and extends over theemitter regions. The gate electrode 109 is formed on top of the gateinsulating layer and more insulating layer 108 is formed around the gateelectrode to isolate the gate electrode 109 from the emitter metal 101.The gate electrode may be created using for example and withoutlimitation a polycrystalline silicon layer.

As shown, not every shield electrode is covered by a gate. A gate oxidelayer and gate electrode do not cover shield trench dielectric 102 andshield trench electrode 103. The shield trenches serve to compensate N+regions and to keep the breakdown voltage high.

FIG. 2 shows a circuit diagram of an IGBT 201 and a diode 202. Due tothe construction of the IGBT, reversed bias, reverse current does notflow through the IGBT. The IGBT is configured such that current flowsfrom the collector C to the emitter E when a voltage greater than thevoltage gate-emitter threshold (V_(ge(th))) is applied to the gate G. Areverse bias applied from to the collector will not result in currentbeing conducted across the IGBT. To overcome this issue prior IGBTcircuit designs place a diode 202 antiparallel with the IGBT 201. In thecontext of the present disclosure, antiparallel means that the device isconnected in parallel but configured to conduct when a reverse bias isapplied to the collector. Referring the diagram, the anode of the diode202 is connected to the collector of the IGBT and the cathode of thediode is collected to the emitter of the IGBT.

According to aspects of the present disclosure IGBT, designs may beimproved using a super-junction MOSFET arranged in parallel with theIGBT instead of freewheeling diode. FIG. 3 shows an aspect of thepresent disclosure wherein the IGBT 301 is structurally to asuper-junction MOSFET 302. Additionally as shown, the IGBT may beconductively coupled to the super-junction MOSFET by way of sharing thesame contact layer. The IGBT depicted is an N-channel IGBT and thesuper-junction MOSFET shown is an N-channel super-junction MOSFET. Thegate G of the IGBT 301 and the gate G of the super-junction MOSFET 302are conductively coupled 303. The IGBT and the super-junction MOSFET arelinked and the V_(GE(th)) for the IGBT and the V_(GS(th)) for thesuper-junction MOSFET should be within a similar range, e.g., within ±2volts of each other. Due to the conductive coupling of the gates and thesimilar activation threshold values for the IGBT and the super-junctionMOSFET, when a sufficient voltage is applied to the IGBT to put thedevice in the ‘on’ state, the super-junction MOSFET should also be inthe ‘on’ state. The collector C of the IGBT 301 and the drain D of thesuper-junction MOSFET 302 may also be conductively coupled 304. Theemitter E of the IGBT and the source S of the super-junction MOSFET maybe conductively coupled 305 as well. The super-junction MOSFET used forthis purpose may include a fast recovery body diode which is created byreducing minority carrier lifetime of the super-junction MOSFET usingmethods such as electron irradiation.

Additionally, the super-junction MOSFET 302 is configured so that whenarranged as described the body diode of the super-junction MOSFET isantiparallel with the IGBT. As such during operation in reverse bias andreverse current mode, the body diode of the super-junction MOSFET actsas a freewheeling diode for the IGBT.

As used herein conductively coupled may mean an electrical connectionbetween two elements that allows electrons to flow from one element tothe other. The electrical connection may be through any conductivematerial such as wire, metallic leads, conductive gel, metallized glass,metallized plastic and the like. Structurally coupled may mean that twoelements are affixed to each other or to the same structure or surface,where the affixation may be flexible or rigid. The structure or surfacemay be any surface known in the art for example and without limitation aPCB, an integrated circuit package, a metal surface, a plastic surface,a wooden surface or similar.

FIG. 4 depicts an embodiment of the present disclosure where the IGBTand super-junction MOSFET that are structurally coupled by the samesubstrate, epitaxial layers and contact layers. As shown, the substrateand epitaxial layers includes both an IGBT 401 and super-junction MOSFET402. Additionally, the two switches share a contact metal 417 and asubstrate contact 411. By way of sharing a contact metal 417 and asubstrate contact 411, the IGBT 401 and the Super-junction MOSFET 402are electrically coupled. As shown the contact metal 417 for thesuper-junction MOSFET 402 is the source metal contact and is inelectrical contact with the Source region 407. The source region may bedoped with the first conductivity type and located in the surface of anepitaxial layer 403. A body region 408 of the second conductivity typeformed deeper in the epitaxial layer 403 and underneath the sourceregion 407. A doped column of the second conductivity type 409 islocated under the body region 408 in the epitaxial layer 403. The rangeof doping concentrations for the source region 407 and body region 408may be as discussed above. By way of example, and not by way oflimitation, the source doping concentration may be of order 2e19 and thebody doping concentration may be of order 1-5e17. V_(th) can be tuned byadjusting body dose and gate oxide thickness.

A drift region of the first conductivity type 406 may be located in theepitaxial layer between the two columns doped with the secondconductivity type 409. Above the drift region may be the gate insulator404, which may be for example and without limitation an oxide layer. Agate electrode 405 is located above the gate insulator 404 and protectedfrom the contact metal 417 by the gate insulator. The gate electrode 405may be for example and without limitation a polysilicon layer. When avoltage is applied to the gate electrode 405 at or above a voltagethreshold (V_(gs(th))) current applied to the drain (For an N-channelMOSFET) at the substrate layer 411 will be conducted vertically throughthe drift region 406, the body region 408 and source region 407 to thecontact metal 417. The drift region 406 and columns 409 are sized anddoped such that their charges balance out horizontally with adjacentcolumns. The concentrations of the columns and drifter region can bemade higher than that of just a drift region in a typical transistor sothat during the ON state they conduct with lower ‘on’ resistance.Additionally the V_(GS(th)) of the Super-junction MOSFET 402 should bechosen such that it is the same or within ±2 Volts of the Voltagethreshold (V_(GE(th))) for IGBT 401.

Under the drift region 406 is a heavily doped bottom layer 410 of thefirst conductivity type. Finally, in conductive contact with the layer410 is the backside contact 411 or drain contact for the super-junctionMOSFET. The heavily doped bottom layer may act as the drain for thedevice with current flowing from the backside contact 411 through thebottom layer 410 and eventually to the contact metal 417.

An IGBT is formed from the same substrate and epitaxial layers 401 asthe super-junction MOSFET 402. As shown a shield trench may separate theIGBT 401 from the super-junction MOSFET 402. The shield trench may belined with a shield trench dielectric 418 which may be made of, withoutlimitation, an oxide layer, as discussed above. A shield trenchelectrode 419 may be disposed on top the shield trench dielectric 418and insulated from the epitaxial layer and substrate by the dielectric.The shield trench electrode may be made from a conductive material forexample and without limitation, polycrystalline silicon.

The IGBT has a lightly doped epitaxial drift region 412 of a firstconductivity type. The doping concentration of this region may be lowerthan the doping concentration of the Super-junction MOSFET 402. A moreheavily doped buffer region 413 of the first conductivity type is formedunderneath the epitaxial drift region 412. Under the buffer region 413is a lightly doped layer 414 of either conductivity type and animplanted bottom layer 415 at the bottom of second conductivity typethat forms the IGBT collector. A backside contact 411 is formed on thebottom of the implanted bottom layer 415. The backside contact 411 maybe a metal layer, which may be made from copper, aluminum or golddeposited on the back surface.

On top of the lightly doped epitaxial drift region 412 is a heavilydoped region 416 of the first conductivity type. A body region 420 islocated on top of the heavily doped region. The body region may be dopedwith the second conductivity type. The body region 420 may have aheavily doped region emitter region 421 of the first conductivity typeformed on top of it.

A shield trench may be formed in the substrate and terminate at thedepth of the lightly doped epitaxial drift region 412. The shield trenchmay be lined with a dielectric 424. A shield trench electrode 425 isdisposed on top of the dielectric and may be at emitter voltage. A gatecomprising a gate insulating layer 423 is formed on top of the shieldelectrode and extending over the emitter regions. A gate electrode 422is formed on top of the gate insulating layer and more insulating layer423 is formed around the gate electrode to isolate the gate electrode422 from the contact metal 417.

Similar to Super-junction MOSFET 402 the V_(GE(th)) of the IGBT 401 isconfigured to be within ±2 Volts of the V_(GS(th)) for theSuper-junction MOSFET. The implanted bottom layer 415 acts as acollector for the IGBT 401 and when a voltage is applied to the Gateelectrodes 422, current at the backside contact 411 flows verticallythrough the implanted layer 415 and epitaxial layers to the emitterregion 421 finally to the contact metal 417.

FIG. 5 shows a bottom view of the device having an IGBT andSuper-junction MOSFET structurally coupled by way of sharing back metaland epitaxial layers. In the shown embodiments, the back side of thechip is being described. In the IGBT portion, the shown region is thecollector and in the Super-junction MOSFET, the region is the drain. Themajority of the substrate space is occupied by the IGBT, implantedsubstrate of the second conductivity type 501. The Super-junction MOSFETsubstrate regions of the first conductivity type 502 are interspersedregularly. In the shown embodiment, the Super-junction MOSFETS arecircular regions separated by IGBTs.

FIG. 6 depicts an alternative embodiment of the present disclosure. Inthis alternative embodiment, the shield trenches have been eliminated inthe IGBT section 601 and Super-junction-like doped columns 606 arecreated underneath the body regions 605 and extend into the drift region607. The super-junction-like doped columns may be of the secondconductivity type as the body region 605. Compared to the IGBT in FIG.4, the relative doping concentration of the first conductivity type forthe epitaxial/drift region is greater in the alternative embodimentshown in FIG. 6. Additionally the drift region 607 extends all the wayto the buffer implant layer 610. Below the buffer is the lightly dopedlayer 611 of either conductivity type, and the implanted layer 612 ofthe second conductivity type that forms the IGBT collector.

The IGBT portion 601 also includes a gate insulating layer 608 formed onthe epitaxial layer. The gate insulating layer 608 protects the gateelectrode 609 from current flowing through epitaxial layer and contactmetal 603. The gate insulating layer may be for example and withoutlimitation a silicon oxide layer. The gate electrode 609 is formed onthe surface of the gate insulating layer 608 and the insulating layerencompasses the gate electrode to electrically isolate the gateelectrode from the metal contact layer 603. The gate electrode may befor example and without limitation a layer of polycrystalline silicon.When a voltage at or exceeding V_(GE(th)) is applied to the gateelectrode current flows from the substrate contact layer 611 through avertical channel formed in the substrate implant region 610, the driftregion 607, the body region 605, the emitter layer 604 to the contactmetal 603.

The Super-junction portion 602 is largely unchanged from the portiondescribed in FIG. 4. It should be noted that in this embodiment theSuper-junction portion 602 and the IGBT portion 601 share a drift region607. The shared epitaxial/drift region may be at the same dopingconcentration for both the super-junction portion 602 and the IGBTportion 601.

FIG. 7 depicts another alternative embodiment according to aspects ofthe present disclosure. Here, the IGBT 701 and the super-junction MOSFET702 are physically separate but structurally coupled by way ofelectrical connections between the gate electrodes, and contacts. Asshown, the construction of the IGBT portion 701 and Super-junctionMOSFET 702 is similar to that of FIG. 4. Unlike the embodiments shown inFIGS. 4 and 6, the IGBT portion has a separate emitter contact metallayer 703, drift region 708, buffer 716, lightly doped region of eitherconductivity type 717 and implanted layer of second conductivity type718 that forms IGBT collector and collector contact 711. Likewise, thesuper-junction MOSFET includes a separate source contact metal layer704, epitaxial/drift region 709, substrate layer 712 and drain contact710.

The operation of the two portions shown is similar to the previousembodiments because the gate electrode of the super-junction MOSFETportion 714 is electrically coupled to the gate electrodes of the IGBTportion 715 through the gate electrode leads 705. Additionally in someembodiments the emitter contact metal layer 703 of the IGBT portion 701is electrically coupled to the source contact metal layer 704 throughthe emitter contact leads 706. Similarly, the collector contact layer711 of the IGBT portion 701 is electrically coupled to the drain contactlayer 710 through the collector contact leads 707. This electricalcoupling of areas of the two device portions allows the portions tooperate together without sharing a common substrate or epitaxial layer.Specifically, the electrical coupling of the gate electrodes for theIGBT portion and the super-junction MOSFET portions means that duringoperation, IGBTs and Super-junctions MOSFETS with closely similar gatevoltage thresholds will operate in synchronized fashion when switchingto the ‘on’ state. Additionally the IGBT portion 701 and theSuper-junction MOSFET portion 701 may be structurally coupled by way ofbeing for example and without limitation, in the same integrated circuitpackage, on the same printed circuit board, or attached to the samesurface.

Function

FIG. 8A shows the function of the IGBT structurally coupled to asuper-junction MOSFET at 25 C 803 according to aspects of the presentdisclosure. Also shown is the function of a lone IGBT 801 and a loneSuper-junction MOSFET 802. The graphs of FIGS. 8A and 8B show current vsvoltage for the different devices. As discussed above, the lone IGBTcurve 801 exhibits a diode like voltage threshold where the currentconducted across the device does not rise until the voltage is ˜0.6Volts at 25 C. At 125 C, the current through the lone IGBT 804 does notrise until ˜0.45 volts. The lone Super-junction MOSFET curve 802 on theother hand shows a linear rise in current conducted across the devicestarting at 0 volts. Similarly at 125 C the rise in current through thelone super-junction device has linear characteristics 805 and is flatterthan the curve at 25 C 802. On the other hand after the voltagethreshold the lone IGBT at both 25 C 801 and 125 C 804 device exhibitsnon-linear behavior. This behavior can be interpreted as the majority ofcurrent being conducted through the Super-junction MOSFET at currentsbelow 0.6-1 amps and due to the non-linear behavior of the IGBT atcurrents above 0.6-lamps, the majority of current is conducted throughthe IGBT portion of the device.

The IGBT structurally coupled and electrically coupled to asuper-junction MOSFET curve 803 exhibits behavior of both a lone IGBTand a lone Super-junction MOSFET. As shown, the device exhibits linearbehavior at low voltages, below 0.6 volts at 25 C and below 0.4 volts at125 C. At higher voltages the device exhibits a non-linear relationshipbetween current and voltages, this non-linear relationship persists from25 C 803 to 125 C 806. Thus the curves clearly show that the IGBTstructurally coupled and electrically coupled to a super-junction MOSFETresolves the voltage threshold problem in prior art IGBT devices becauseat >0 volts the device begins to conduct current. The device alsomaintains the positive aspects of the IGBTs because after the voltagethreshold, the device exhibits the typical non-linear IGBT behavior.

FIGS. 9A and 9B show the reverse current and reverse bias function ofthe IGBT structurally coupled and electrically coupled to asuper-junction MOSFET current vs voltage curves at 25 C 901 and 125 C903 respectively according to aspects of the present disclosure. Thecurrent vs voltage graphs also show the function of a normal IGBTco-packaged with an anti-parallel Fast Recovery Diode at 25 C 902 and125 C 904. The graph shows that for a normal IGBT 902 at low voltages,no current is conducted across the device. The curve indicates that inthe reverse bias and reverse current direction conductance across thedevice is dominated by conductance through the body diode of thesuper-junction MOSFET portion of the device. The body diode of thesuper-junction MOSFET could be considered acting as a freewheeling diodefor the device. Thus, the device also fulfills the need for afreewheeling diode in lone IGBT devices and has lower conduction lossescompared to co-packaged FRD.

While the above is a complete description of the preferred embodiment ofthe present invention, it is possible to use various alternatives,modifications and equivalents. Therefore, the scope of the presentinvention should be determined not with reference to the abovedescription but should, instead, be determined with reference to theappended claims, along with their full scope of equivalents. Anyfeature, whether preferred or not, may be combined with any otherfeature, whether preferred or not. In the claims that follow, theindefinite article “A”, or “An” refers to a quantity of one or more ofthe item following the article, except where expressly stated otherwise.The appended claims are not to be interpreted as includingmeans-plus-function limitations, unless such a limitation is explicitlyrecited in a given claim using the phrase “means for.”

What is claimed is:
 1. An apparatus, comprising: an insulated gatebipolar transistor (IGBT) having a gate comprising a gate insulatinglayer formed on top of a first shield electrode extending into adriftregion of a first conductivity type, the insulated gate bipolartransistor further having an implanted layer of a second conductivitytype opposite the first conductivity type, a buffer layer of the firstconductivity type between the drift region and the implanted region anda lightly doped layer of either the first conductivity type or thesecond conductivity type between the buffer region and the implantedregion; and a super-junction metal-oxide semiconductor field effecttransistor (SJ-MOSFET) having a drift region of the first conductivitytype, a heavily doped bottom layer of a first conductivity type, whereinthe drift region is of the first conductivity type, wherein the IGBT andthe SJ-MOSFET are structurally coupled by a common substrate, wherein anemitter of the insulated gate bipolar transistor and a source of thesuper-junction metal-oxide semiconductor field effect transistor areconductively coupled by a contact metal, wherein a collector of theinsulated gate bipolar transistor and a drain of the super-junctionmetal-oxide semiconductor field effect transistor are conductivelycoupled by a backside contact.
 2. The apparatus of claim 1, wherein agate of the IGBT and a gate of the SJ-MOSFET are conductively coupled.3. The apparatus of claim 1 wherein a body diode of the MOSFET isanti-parallel to the IGBT.
 4. The apparatus of claim 1 wherein in an“on” state at currents less than 1-2 Amps the majority of charge isconducted through the SJ-MOSFET.
 5. The apparatus of claim 1 wherein inan “on” state at currents greater than 1-2 Amp the majority of charge isconducted through the IGBT.
 6. The apparatus of claim 1 wherein theSJ-MOSFET includes a fast recovery body diode.
 7. The apparatus of claim6 wherein the fast recovery body diode is created by bombarding theSJ-MOSFET with electrons before packaging.
 8. The apparatus of claim 1wherein the SJ-MOSFET acts as a freewheeling diode.
 9. The apparatus ofclaim 1 wherein the IGBT is a planar gate insulated gate bipolartransistor.
 10. The apparatus of claim 1 wherein the insulated gatebipolar transistor and the super-junction metal-oxide semiconductorfield effect transistor are configured to have gate source thresholdsthat are within ±2 Volts of each other.
 11. The apparatus of claim 1wherein the insulated gate bipolar transistor is arranged parallel withthe super-junction metal-oxide semiconductor field effect transistor.12. The apparatus of claim 1 wherein super-junction metal-oxidesemiconductor field effect transistor structures are interspersedbetween insulated gate bipolar transistor structures in the commonsubstrate.
 13. The apparatus of claim 1 wherein the insulated gatebipolar transistor shares a drift region with the super-junctionmetal-oxide semiconductor field effect transistor and wherein the shareddrift region is at a same doping concentration for both the insulatedgate bipolar transistor and the super-junction metal-oxide semiconductorfield effect transistor.
 14. The apparatus of claim 1 wherein theinsulated gate bipolar transistor includes a second shield electrodebetween adjacent gates.
 15. The apparatus of claim 1, wherein a bottomof the drift region in the IGBT is position higher than a bottom of thedrift region in the SJ-MOSFET.
 16. The apparatus of claim 1 whereinthere are a plurality of body regions, and doped columns and wherein theplurality of doped columns are extend into the drift region and whereinthe body regions and doped columns have a same conductivity type.